Separation of 2-keto-l-gulonic acid from fermented medium

PURPOSE: To simply obtain the subject compound useful as a precursor of ascorbic acid in a good yield by successively removing impurities and inorganic cations from a fermented medium containing the Ca salt of the keto-L-gulonic acid and subsequently separating the keto-L-gulonic acid. CONSTITUTION: Insoluble impurities are separated from a fermented medium containing the Ca salt of 2-keto-L-gulonic acid by a centrifugal separation method, etc., preferably after coagulated with a coagulating agent. Inorganic cations are removed from the medium preferably by the use of a sulfone type ion exchange resin. Finally, the objective compound is separated from the medium free from the insolubles and the inorganic cations generally by a crystallization method. COPYRIGHT: (C)1990,JPO